1. Field of the Invention:
The present invention relates to quaternary ammonium hydroxide-containing polymers and to their method of preparation.
2. Brief Description of the Prior Art:
Cationic electrodeposition as practiced on an industrial scale involves immersing an electroconductive article in an aqueous dispersion of a polymeric material which contains cationic groups such as quaternary ammonium salt groups or amine salt groups. An electric current is passed through the dispersion between the electroconductive article as cathode and a counter electrode as anode to cause a deposition of the coating on the cathode. During the electrodeposition, acid is generated at the counter electrode and continuously builds up in the bath where it can corrode equipment and raise the conductivity of the bath making it more difficult to electrodeposit smooth uniform coatings.
The prior art has recommended numerous ways to control this acid build-up such as by subjecting the bath to ultrafiltration and electrodialysis. However, these methods have shortcomings associated with them in that they require additional equipment costs as well as the expense of monitoring and maintaining the additional equipment.